drm/i915/vrr: Add function to check if DC Balance Possible

drm/i915/vrr: Add function to check if DC Balance Possible

Add a function that checks if DC Balance enabling is possible on the
requested PIPE. Apart from the DISPLAY_VER check, account for current
firmware limitations, which only allow DC Balance on PIPE A and PIPE B.

v2: Rephrased commit message. (Ankit)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20251223104542.2688548-9-mitulkumar.ajitkumar.golani@intel.com